Mechanical musical instrument



June l 1926.

G. WHITEHOUSE MECHANICAL MUSICAL INSTRUMENT Filed Nov, 29, 1922 2 Sheets-Sheet 2 Cil Patented June 1, 1926.

UNITED STATES l 1,537,204 PATENT OFFICE.

Y GRANT WHTEI-OUSE, OF NEW YORK, N. Y., ASSIGNOR TO WESER BROS., vINC., OF

NEW YORK, N. Y., A. CORPRATIONDF NEW YORK.

lilE-CHANICAL MUSICAL INSTRUMENT.

Application filed November 29, 1922. Serial No. 603,908.

My invention relates generally to pneumatically-operated musical instruments, such as player-pianos, organsand other musical instruments of the well-known type in which a perforated music-sheet is caused to travel Iover a tracker-bar formed with a series of air-ducts connected with the playing devices, and my improvements relate particularly to the music-sheet winding and rewinding `mechanism by which the instrument is operatively controlled, and with novel devices controlled by the positionY of the music-sheet on the tracker-bar for terminating the operation of such rewinding mechanism. y y y The objects of my'invention are, among other things, chiefly to provide a simple, vefficient and automatic means connected with any selected one of the customary note-controlling air-ducts in the tracker-bar normally used for operating the playing devices, which will immediately terminate the operation of the motor for rewinding when the sheet has travelled backwardly off the tracker, thereby avoiding, among lother things, the undesirable slapping noise caused by the rapid revolution of the forward end of the music-sheet against the tracker box after such end has become disengaged from the Catch in the take-up roll. Heretofore it has been proposed to use special air-ducts in the tracker to control such winding and rewinding mechanism usually cut outside the range of the 88 notes, yor to block off and use exclusively for such control one 'of the 88 note music-ducts, generally one of the outside ducts.

By my improvements any one of the customary 88 noteair-ducts in the tracker may be operatively connected with my improved control device to accomplish an instantaneous shutoff for the motor on the rewind when the paper leaves the tracken har thereby exposing a suflicient number of air-ductsV to equalize the exhaust pressure between the pump-ing bellows and action wind-chest and without affecting tne use ofv such air-duct in controlling` the playing 4of the particular note in the musical composition in the forward run of the music-sheet over the tracker-bar.Y

A further object of my invention is to provide simplified yetinstantaneously yeifective shut/sofi' valve for the motor-rewind, located in the main wind-trunk, the action of which is inaugurated by the automatic control device hereinbefore referred to, so that the motor may not undersirably overrun but 1s always under the direct control lofv the music-sheet as it travels tracker-bar.

'With the foregoing and other objects in view, the invention comprises the features of construction, the parts and combinations thereof and the mode of operation as hereinafter described and then particularly pointed out in the appended claims.

Of the drawings, Fig. 1 is a front elevation of a player-piano with parts broken out and the front casing removed which illustrates an embodiment of the inaf'ention in a diagrammatic way;V

Fig. 2 is an enlarged plan view of the pneumatic containing the valve mechanism;

Fig. 3 is a side elevation of the pneumatic shown in Fig. 2;

Fig. et is a section plan view taken on the line fl-t of Fig. 5 looking in the direction of the arrows;

Fig. 5 is a longitudinal sectional view taken on the line 5-5 of Fig. 4;

Fig. 6 is a sectional plan view taken on the line 6 6 of Fig. 5;

Fig. 7 is a sectional plan view taken on the line 7-7 of Fig. 5;

Figs. 8 and 9 are longitudinal sectional views taken on the lines 8 8, 9-9 of Fig. t respectively; and

v Fig. 10 is an enlarged detail view in section showing the valve for shutting-off the motor connection with the main exhaust; and Fig. 11 is an enlarged Idetail view of the gate-box .shown in Fig. l.

Similar numerals refer to similar parts throughout the several figures.

Referring to Fig. l, the player-piano which is chosen for a preferred embodiment of the invention may be of any usual or suitable construction, comprising, so far as shown, the frame and supporting case il, the tracker-boX 12 with the tracker-bar lll provided with the customary row of notecontrolling air-ducts l5 on its face. Journailed in the tracker-box 12 are the takeup roll 16 and the music roll 17, the latter carrying the music sheet 18. Operatively connected with the take-up roll 16 and music-roll 17 is the gearing 19 driven from the motor 20 by the sprocket chain 2l in the usual manner. The gearing 19 is shifted back over the sfedapted to 'Close the pipe liii-'hen by the rewind lever 22 'lor windinfcil and rewinding the music-sheet 18 in the eustonn ary inanner, except as hereinafter set forth, the present Yiinproveinents not directly relating with the structural details, arrangement and operation o'lI such devices. its shown in Fig. 1 the rewind lever 22 is connected by the link 23 to the rock-shirtlv Q-lwhich actuates the rod 25 to inove the clutch-shitting` lever 26 pivoted on the Ibracket 26a fastened to the tracker-box .12 by which the niotor 20 is operatively connected either' with the take-up roll 'lo or with the inusicroll driver for rewinding the music-sheet 18 troni the take-np roll 1G back onto the music-roll 17. rlhe inotor 2O is connected by the inain wind-trunk 27 with the customary pumpingl bellows (not shown) which produce the required exhaust or vacuum pressure used as the inotive power in the playerpiano.

To control the action ot the inotor 2O 'troni the illusie-sheet 18 upon the rewind ot the latter over the tracker-bar lll, have devised the following' ineehanisin which is shown in detail .in Figs. 2-10, the location thereotl in the ease 11 beingl illustrated in Fig. 1. Such inechanisni comprises the pneun'iatic 28 having' the movable leat 2f) hinged at 30 to the body S31 ot the pneumatic (Fic and 9) in the us ial n'ianner to 'torni the inaiu chainber $32. rlfhe spring iueuiber fm (Fig. il) secured to the lea't 2S) and body 231 norinally tends to .raise the lea't 'itl to its Fig. 9 position; and the ehaniber 32 is connected through the port Bel, nipple C and tube 3G wth the wind-ehest- 87 (shown diagrannnatically in 1) to hold the lentl 2S) in its collapsed Fig. 5 position against the tension o'lf the spring' 33 when the player action is rendering the selection by the torward travel ot' the music-sheet 18 over the tracker-bar ht. Upon the under side otA the lcaty 2S) is at'iixed the telt button 238 attached to the punch-Halve El!) 'toru'ied ot leather or other tle.\;ible inaterial which is adapted to open and close the port Ll0 (Figs. 5 and 7) connected by the passage 40 through the conduit Lll (Fing (j) to the nipple d2 connected by the tube 4i to any selected. in this embodiment, the outer air-duct L'il in the traclnrr-lrar lfl; (Fig. l). rl`he valve chainber 4to' is connected by the conduit 1T with the nipple on which the tube fil-9 is secured leading' to the nipple 5t) in the faire-lion 5l. (Fig. 1).

rlbe interior ot the valve-box 5l is shown in Fig. 10; such box is mounted on the wind-trunk 2T and 'tits over and enelose the outer end ot the pipe 52 leading1 to the n'iotor 20. The side ot the box 5l. opposite the pipe 52 is torined with the recessed chamber 33 and the puneh-valve 54 is atlifed across the top oi the ehainher 53 and -a'tnios-f pheric pressure is adinitted to the chaniber a3 through the nipple 50 and tube 119.

le'terring to Figs. (i and t), the conduit tl is extended through the body o1 in alinen'ient with the nipple to itorin the passage Ll1 connected with the vertical poi't :35 opening' into the circular recessed chaniber .Sti sealed troni the inain chainber by the disk 5T. Adjacent the port 55 is a similarly-cut port 55 connected to the nipple 5S) on which the tube t3() is fastened to con'nnunicate with the usual action pneumatic (S1 employed for sounding' the last note in the key-board correspondingr with the air-duet All. The flap 'alve (S2 is secured to the tloor oit the chainber 5G and is adapted to close the port 55 so as to liireali the connection between the pneumatic (i1 and the note duct Llilduring the rewind. then the valve (S2 is in its open position (shown by dotted lines in Fig. 9), a direct exhaust, connection is maintained between the nipple il). and the nipple 59 to enable the action pneumatic 61 to sound the proper note in the inusieal composition when the note duet 44 is uncovered by its registeringl perforation in the music-sheet 18. its shown in Fie'. 1 the wind-trunk 2T has a supplen'rentary tube 63 ot sinall size connected witn the wind-chest 3T, so that the chauiber l2 in the pneumatic QS niay be under a slight air tension sutlicient to hold the lea't 29 collapsed at all tinies during the rewind (irrespective ot an;v uncovering' ot the note ductI lil-1 'v the unisi sheet), until the inusic sheet 1H has reached the position shown in Fig. l so that. a sutiicient nuinber ot ducts l5 alone' ith the duct -lr-Ll have been uncovered to break the vacuuin exhaust in the corresi'mndingr player actions to allow the spring' il?) to litt the leat 2) and raise the valve 35) which iuaugurates the action ot the niotor shut-ott control.

le'lerrine' to Figs. 1 and l1V the linli 2f) has pinned thereto the lower end ot the roule lever (if-l 'tulcrun'ied on the stud t' with the upper end ot the lever (ldlslidably connected with the outer end of the valve-rod (SG which actuated in the gate-box (ST. This gatebox (3T is divided into three separate chainbers (Srl. (5S). and Tt) by the partitions T1 and 72 respectively. rl`he lett-hand ehainber (3S tlfigr. ll) is connected by the pipe T- to the usual action pneumatic chamber tor the aetion pueuuiatics til. while the iniddle chainber {il} is connected by the pipe 7l; to the wind-chest 3T. The richt-hand chamber Tt) is connected by the pipe T5 to the wind truul 2.7. all as shown` in Fig. 1. llVit-hin the chaniber (S8 is the valve TG fastened to the inner end of the rod 66 which valve is adapted to open and close the port TT 'torlned inv the partition 71; within the chainber 70 is the valve 78 fastened to the rod (56 to open aufL close the port Tt) torined in the partition El bleed passage St) is also eut in the partition 71 as shown in Fig. 11. The valves 76 and 7 8 are so spaced on the rod (33 that in one position the valve 7 6 opens directly connected with the action pneumatics 61 and the wind trunk 27 shut ofi1 i'rom the wind-chest 37. During the rewind when the lever 22 has moved the linl 23 to the left (Fig. 1), the valve-rod G6 is actuated through the rock-lever 64 to shift the positions ot the valves 76 and 78 so as to cut oit the chamber 63 from the wind-chest 37 by the closing of the port 77, while the port 79 is opened by the valve 7 8 thereby connecting` the wind-chest- 37 only with the wind-trunk 27 with a. slight exhaust pressure maintained in the chamber 63 and action pneumatics G1 through the bleed opening` 80.

Illhe operation of my improved control device during the travel of the music-sheet 18 over the tracker-bar 14 during the wind and rewind is substantially as follows. When the player actions are rendering the musical selection according to the perforations in the music-sheet 18, the leat 29 is collapsed by the exhaust connection through the nipple 35 with the wind-chest 37'against the torce ot the spring 33. The collapsed leaf 29 forces and holds the valve 39 against the port 40 which shuts ott communication between the nipple 42 connected with the air-duct 44 in the tracker 14 and the nipple 48 connected by the tube 49 with the nipple 50 communi ating with the chamber 53 in the valve-box 51 to hold the valve 54 away from the oritice ot the pipe 52 leading to the motor 20. Such valve 39, therefore, maintains a. normal operative exhaust connection between the tracker duct 44 and its corresponding action pneumatic G1 to operate the note corresponding with the last note on the key-board as the musical coinposition is being played according to the pertorations in ythe music-sheet, and the motor 2O is under operative exhaust connection with the wind-trunk 27.

However, when the handle oit' the rewind lever is moved to the right (Fig. 1) to shift the gearing' 19 tor rewinding, the valve-rod .66 is also moved to the right through the link and rock-.lever to cut ott, as has been hereinbetore described, the wind-chest 37 trom the series of action pneumatics comprising the player action, oty which the pneumatic 61 is one, while at the same time the opening ot the valve 7 8 (moved tothe right) in the gate-box 67 provides a' direct connection from the wind-chest 37 through the chamber 69, port 79 chamber 70 and pipe 75 to the wind trunlt27 and motor 20.101' the music-roll rewind. lieanwhile during such rewind the suction exhaust is maintained in the chamber 32 ot the pneumatic 28 from the wind-chest 37 through the tube 3G, nipple 35 and port 34 as hereincet'ore described, only until the music-sheet 13 leaves the tracker-bar 14. Vhen this music-sheet 18 reaches the position shown in Fig. 1, the exhaust tension in the chamber 32 is broken by the equalization to atmospheric pressure derived through a series ot tracker air-ducts 15 through the action pneumatics 61, windchest 37, tube 36 and nipple 35. Instantly the leaf is raised by the spring),` v33 which alsoliits the valve 39 irom the port 40 thereby connecting the chamber'46 through the passage 40a and conduit 41 with the nipple 42 connected by the tube 43 with the tracker opening 44; at the same time the chamber 46 is connected to theV conduit 47, nipple 48 and tube 49 with the chamber 53 (Fig. 10) ot the valve-box 51 through the nipple 50, thereby breaking the exhaust pressure in this chainber 53 which holds thel valve 54 away from the orifice ot the pipe 52 as hereinbetore explained. rhereupon atmospheric pressure in this chamber 53 immediately forces the valve V54 against the pipe 52 as shown in Fig. i() which causes the stoppage ot the motor 2O by cuttingoit the operative suction connection normally maintained throughout the wind-trunk 27 by the pumping,l bellows (not shown).

rlhe foregoing construction embodies the underlving` principles of my invention, but furious changes or modifications may be n'iade in the structural details and arrangement of the parts without departing from the scope ot 'my improvements. However, the foregoing' is suiiicient to disclose the basic principles and advantages ot' my invention as installed in a` player-piano to attain an automatic and instantaneous stopping' of the motor upon the rewind ot the music sheet.

I claim as my invention:

1.1na mechanical musical instriunent controlled by a perforated music-sheet and 'raclrer-bar, a. music-sheet winding device, a pneumatic motor to aetuate saine, a source et exhaust pressure to operate said motor, atraclier-bar having` air-ducts therein controllingv separato action pneumatics, and a valve held open by said exhaust pressure during; they forward travel ot' the sheet to close and stop the motor after the rewind, said valve being actuated when the musicsheet uncovers a sutiicient number of said airducts upon leaving the tracker-bar to equalize the exhaust pressure through said action pneumatics.

Tin a mechanical musical instrument controlled a perforated music-sheet and lli) li'z clair-har, a music-sheet Winding device, a pneumatic niotor to actuate saine, a source ot exhaust pressure to operate said n'iotor, a tracker-har having' air-ducts therein controlling separate action pneiiinatics, and an independent pneumatic valre norinallv held ogen through exhaust pressure h v the .inusicsheet during' its t'oi'n'ard travel across the tracker-hin' to close and stop the inotor atter the rewind. said valve being' actuated when the music-sheet uncovers a suilieieut niunher ot said air-ducts upon leaving the tiacl;e.r liar to equalize the exhaust pressure through si id action pneuniaties.

9). in a niechanical inuisical instrument controlled liv a perforated music-sheet and tracker-liar, a music-sheet ivindiniiV device, a pneumatic ii'iotor lo aetuate saine. a source ot exhaust pressure to operate said inotor7 a tracker-hai' having' air-ducts therein controlling separate action preuinatiesT and an independent pneumatic 'alve norinalliv held open through e'haust pressure liv the iiiusic sheet during' its Ytoi'ivard travel across the tracker-har to close and stop the inotor utter the rewind, said valve heine' controlled through a predetermined air-duct and actuated when the iunsic sheet uncovers a sutticient nuinher oit said air-ductsA upon leaving' the ti':icl-:ei'l ar to equalize the ein aust pressure throun'l sa id action pneiiiiiatics.

`i. lu a mechanical niusical instrun'ient controlled h v a perforated niusic-slieet and tracker-hai; a music-sheet Winding' device, a pneumatic niotor to actuate saine, a source oif exhaust pressure to operate said n'iotor7 a trackerliar having' air-ducts therein controlling' separate action pneuii'iatics, and a valve norniallv held open through exhaust Dressure while the music-sheet is moving' in either direction when covering' the air-ducts in said tracker-liar. hut closed to stop the inotor when a sui'lieient nuu'ilier oi said air-ducts ren ain exposed hy the ii'iusie-sheet leaving; the tracker-liar to equalize the exhaust pressure through said action piieiiiiiatics.

ln a mecha/,al nusiral instrument controlled lijf a .)ei'torated iiiiisicslieet and tracker-lian ay niusic-sheet Winding' device, a nneuniatie niotor to actiiatc saineL a si `iiice oil` ,Xhaust pressure o operate said inotor, a l'i'ackeiharhaving' air-ducts therein controlling' separate a tion pneuiaaties, and an independent pneuniatic valve norinallv held open through exhaust 'pressure ivhile tlie iiiiisic-slieet is inoving in either direction when covering' the air-ducts in said trackerhar. hut closed lo stop the inotoi.' when a suttlcient nuinl er ot said air-ducts reinain e11- pcsed hy the music-sheet leaif'ing' the traclen hai' to equalize the exhaust pressure through said action pneiunatics.

('S. In a n'iechanical musical instrument controlled h v a pertorated riusii i 'traclerfoarAg niiisic-sheet 'i exhaust pressure through said action pneuinzit-ies.

'i'. in a mechanical niusieal ins'runieiit controlled by a perforated niusicsheet and tracker-har, a music-sheet Winding' dei'ice, a pneumatic niotor to actuate saine in either direction, a source et Xhaust pressure to operate said niotor, a tracker-har having;` airducts therein, a t'avelling music-sheet reg; isteringg ivith said ducts,l a note-pievini;v action con'iprising' a series ot action pneuinatics controlled itroiu said air-ducts7 and a valve normally held open by said exhaust pressure n'liile the music-sheet is iii-ovine' in either direction when eoif'eringl said air-ducts, hut lirougght into operation to stop the niotor u'lieuevei.' a sul'lieient nun'ilier oi ahi-ducts are uncovered on the rewind to equalize said cf:- haust pressure to atmospheric pressure tlf. ougrh said player action.

ln a mechanical n'ius'cal iuslriinicnt controlled hy i perl'oraled music-sheet and t:'ac. er-liar7 a iiiusic-sheet Winding device,

pneumatic niotor to actuate saine in either direction, a source ot exhaust pressure to operi-ile said niet-or, at ticker-har having air ducts therein, a travelling music-sheet rec'- isl'ering with said ducts, a note-playing action comprising' a ot action piieuseries niatics controlled ti'oin said air-ducts7 and an indcpendei'it iiincuinatie valre nornially held open hy said exl aust pressure while the music-sheet iiioif'in in either direc-- tion vvhen covering` said air-duets, hut liirouc'ht into operation to stop the niotor Whenever a sutlicicnt nuinher oli' air-ducts are ineovered on the reivind to equalize said exhaust pressure itor operating;` said valve to atmospheric pressure through player action,

S). ln a nieclianical niiisical instrument controlled hy a perforated illusie-sheetand tracker-liar, a music-sheet Winding` device, a pneumatic iiiotor to actuate saine in either direction, a source oit' exhaust pressure to ope 'ate said inotor, a tracker-hai' having' airducts therein, a travelling1 inusic-sheet registering with said duets, a note-playing action cci'i'iprising` a series oiI action pneumatics controlled ii'roni said air-ducts and 'i comprising a pneuinat-i'call7 operated lill) lll) valve mechanism connected With one 0f said air-cucts and its action pneumatic, normally held open by said exhaust pressure Whilel the music-sheet is moving in either direction when covering said air-ducts, but brought into operation to stop the motor Whenever a suliicient number of air-ducts are uncovered on the rewind to equalize the exhaust pressure for operating said valve mechanism to atmospheric pressure through said player action.

lO. In a musical instrument controlled by a perforated music-sheet and air-ducts cut in a traclrersbar connected With separate action pneumatics, a Wind-chest under exhaust pressure, a control pneumatic under spring tension connected with the Wind-chest and collapsed thereby, and a normally open valve interposed between a predetermined tracker-duct and its action pneumatic, but closed when said exhaust pressure is cut off from the control pneumatic and said tracker-duct is uncovered by the sheet.

ll. In a musical instrument controlled by a perforated music-sheet and air-ducts cut in a tracker-bar connected With separate action pneumatics, a Wind-chest under exhaust pressure, a valve mechanism controlling the movement of the music-sheet, a control pneumatic under spring` tension connected with the Wind-chest and collapsed thereby, and a second valve between a predetermined tracler-duct and said valve mechanism normally closed by said control pneumatic When collapsed, but opened by the lifting of said control pneumatic when said exhaust pressure is cut off from said valve mechanism and said tracker-duct is uncovered by the sheet.

l2. ln `a pneumatic playing attachment for musical instruments, the combination with a Wind-chest under exhaust pressure, of a control pneumatic under spring tension connected with the Wind-chest and collapsed thereby, and a valve normally closed by said pneumatic when connected With the Wind-chest and interposed between an open port and an exhaust port, said valve being opened by the spring in said pneumatic when the exhaust pressure in said pneumatic is cut olf from said Wind-chest.

13. ln a pneumatic playing attachment for musical instruments, the combination With a Wind-chest under exhaust pressure, of a control pneumatic normally under spring tension connected With the Windchest and collapsed thereby, and a valve normally closed by said pneumatic when` collapsed and interposed between an open port and an exhaust port, said valve being opened by said pneumatic When expanded by said spring` after the exhaust pressure in said pneumatic is cut olf from said Windchest.

le. The combination With a perforated music-sheet, of a tracker-bar having airducts and a pneumatic control device comprising` a spring-tensioned pneumatic normally expanded, a wind-chest under exhaust pressure connected to said pneumatic to hold saine collapsed, a valve interposed between one of said air-ducts and pneumatic nor` nially closed thereby when collapsed and said air duct is closed by t-he music-sheet, but opened by said spring when a suiiicient number of air-ducts are exposed bythe absence of the music-sheet on said tracker-bar to equalize the exhaust pressure in said pneumatic through said Wind-chest.

l5. ln a musical instrument controlled by a travelling` perforated music-sheet registering With air-ducts in a tracker-bar, separate action pneumatics connected with the airducts, a vrind-chest under exhaust pressure, a valve mechanism connected with the Windcliest controlling the travel of the musicsheet, a control pneumatic under spring,l tension connected *with the wind-chest and collapsed by the exhaust pressure therein, and a normally open. valve between a trackerduct and its action pneumatic, but closed when the exhaust pressure is cut off from the control pneumatic after a sufficient number of said tracker-ducts are uncovered on the ren-.find to equalize the exhaust pressure in said valve mechanism to atmospheric pressure through said action pneumatics.

1G. ln a musical instrument controlled by a perforated music-sheet and air-ducts in a tracker-bar connected with separate action pneumatics, a Wind-chest under exhaust pressure, -a control pneumatic under sp ing tension held in inoperative position by said exhaust pressure during` the sheets forward travel, but brought into operation after the sheets reverse travel when said exhaust pressure is cut olf from the control pneumatic after the Wind-chest and the action pneumatics art equaliacd to atmospheric pressure through uncovered air-ducts.

l?. ln a musical instrument controlled br a perforated music-sheet and air-ducts in tracker-bar connected with separate action pneumatics, a wine-chest under exlia pressure, a control pneumatic under spring` tension held in inoperative position by said exhaust pressure during the slieets forward travel With the action pneumatici; connected with their respective air-ducts, but brought into operation after the sheets reverse travel when said exhaust pressure is cut off from the control pneumatic after the Wind-chest and the action pneumatics are equalized to atmospheric pressure through uncovered airducts.

18. ln a musical instrument controlled b v a perforated music-sheet and air-ducts in a tracker-bar connected with separate action pneumatics, a Wind-chest under exhaust pressure, a control pneumatic under spring lill) tension closed b v said exhaust pressure during the sheets forward travel, but opened by said spi-irre' after the sheets reverse travel when said exhaust pressure is cut oit' `from the control pneumatic after the Wind-chest and the action pneumatics are equalized to atmosplarie Vpressure tliroug'h uncovered airducts.

i5). Vin a musical instrument controlled b v a periiorateiil musicesheet and air-ducts iin tracl-:er-bar connected with separate action pnevuinatics,y a Wind-chest under exhaust pressure, a control pneumatic under spring tension closed by said exhaust pressure during the sheets 'forward travel with the action pneumatics connected with their respective air-ducts, but opened bv said springafter the shects reverse travel when said exhaust pressure is cut oit' 'from the control pneumatie after the Wind-chest and the action pneumatics are equalized to atmospheric pressure through uncovered air-ducts.

20. In a mechanical musical instrument controlled by a pertorated music-sheet and tracker bar, a 1nusic-sheet winding` device, a pneumatic motor to actuate saine, a source ot exhaust pressure to operate said motor` a tracker-bar having airducts Connected with rseparate action pneuniaties, a windchest connected with said exhaust pressure', a vcontrol pneumatic under spring' tension having` air connections betweenL one of said air-ducts, its corresponding action }')neu1natic, and to an exhaust control device, said control pneuina'ic M ing` held collapsed against spring ten4 sion during the music-sheets 'forward travel by exhaust pressure irom the wind-chest thereby providing a direct connection between said air-duct and its action pneumat-icz but opened by said spring when a freel connection is made between the air ducts and the exhaust control device after the completion ot the reverse travel ot the music-sheet.

GRANT lVHl TEH OUH E 

